LEC - 7.2 - Beta & Calcium Blockers Flashcards
Location of Beta Receptors:
Heart (stimulation)
Bronchial, uterine, and vascular smooth muscle (relaxation)
Adipose tissue (lipolysis)
2 types of Beta Blockers:
Nonselective
Cardioselective
These drugs have similar antihypertensive effects irrespective of additional properties
Inhibit the secretion of renin and the formation of angiotensin I
Beta Adrenergic Blockers
Therapeutic applications of Beta Blockers
decreases cardiac workload and can ease the symptoms of angina pectoris. By slowing conduction through the mycardium, they treat dysrhythmias. They are also included in the treatment of heart failure, MI and migraine.
These beta blockers block both beta1 and beta2 receptors and so affect the heart, lungs, vascular smooth muscles, kidneys, GI, etc
Nonselective Beta Blockers
These bete blockers work by blocking beta-1 receptors, which prevents epinephrine from binding to these receptors. As a result, these medications block the effects of epinephrine, also known as adrenaline, in order to decrease heart rate and the contractility of the heart
Cardioselective Beta Blockers
Examples of Nonselective Beta Blockers:
ropranolol
nadolol
timolol
pindolol
labetolol
carvedilol
Examples of Cardioselective Beta Blockers:
metoprolol
atenolol
esmolol
betaxolol
Non Cardiovascular Uses for Beta Blockers:
Migraine
In anxiety provoking situations
Glaucoma
Hyperthyroidism
Pheocromocytoma
Alcohol withdrawal
Oesophageal varices
Advantages of Beta Blockers
No postural hypotension
No salt and water retention
Low incidence of side effects
Low cost
Once a day regimen
Preferred in young non-obese patients, prevention of sudden cardiac death in post infarction patients and progression of CHF
Side effects of Beta Blockers:
Fatigue, lethargy or decreased work capacity
Loss of libido or impotence
Cognitive defects like forgetfulness
Adverse effects of Beta Blockers:
Bronchoconstriction
Bradycardia
Cold extremeties
CNS side effects
Heart Failure
Hypoglycemia
Rebound hypertension
Advantages of cardio-selective over non-selective:
Safe for use in:
Asthma
Diabetes mellitus
Peripheral vascular disease
Preferred in young non-obese hypertensive
Angina pectoris and post angina patients
Post MI patients – useful in preventing mortality
In old persons, carvedilol, which has a vasodilatory action can be given
Lowers BP directly by blocking the sympathetic receptor in arterioles causing the vessels to dilate
Alpha Adrenergic Blockers
These drugs are not the first-line drugs for HTN because long-term clinical trials have shown them to be less effective at reducing the incidence of serious cardiovascular events than diuretics.
Alpha Adrenergic Blockers